#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int main(){
    int arr[10];
    cin>>arr[0]>>arr[1]>>arr[2]>>arr[3]>>arr[4]>>arr[5]>>arr[6];
    sort(arr,arr+7);
    double s=arr[1]+arr[2]+arr[3]+arr[4]+arr[5];
    printf("%.2lf",s/5);
    return 0;
}
